Embodiments of the present invention relate to reading data, and more particularly to memory devices and mobile devices including the same.
When reading data of a resistive memory device, extra reference bit lines may be connected to reference cells. When the extra reference bit lines are adopted, the reference cells and the reference bit lines may be formed through same processes as memory bit lines and memory cells are formed. Therefore, process variations may influence characteristics both of the memory cells and the reference cells. Particularly, the extra reference bit lines may be adopted by a Magnetoresistive Random Access Memory (MRAM), which may have a relatively small cell resistance and little difference of resistances corresponding to two different logic values.
When the extra reference bit lines are adopted, resistance matching between the memory bit line to be sensed and the reference bit line providing a reference may be necessary. Particularly, in case of the MRAM, which may have a relatively small cell resistance, when resistances of the memory cell and the memory bit line have little difference, sensing margins may be reduced due to a difference in the resistances of bit lines. When the bit lines are formed through a double patterning process, critical dimension (CD) distributions may be varied according to exposure processes of the double patterning process. When the CD distributions are varied, resistances of the bit lines may also be varied. Therefore, the sensing margin may be greatly reduced.